Bug 1451469 - Complete hooking up of the sampler thread. r=botond,nical

This makes the APZ sampler thread be the render backend thread whenever
webrender is being used (not just when async scene building is enabled).

MozReview-Commit-ID: L9lmopd3pe7

--HG--
extra : rebase_source : a23793bf704a0bf3bc7ba6568ecfe5faa5720415

gfx/layers/apz/public/APZSampler.h

@@ -20,6 +20,7 @@ namespace mozilla {
 class TimeStamp;
 
 namespace wr {
+struct Transaction;
 class TransactionWrapper;
 struct WrTransformProperty;
 struct WrWindowId;
@@ -51,9 +52,11 @@ public:
    * which thread it is.
    */
   static void SetSamplerThread(const wr::WrWindowId& aWindowId);
+  static void SampleForWebRender(const wr::WrWindowId& aWindowId,
+                                 wr::Transaction* aTxn);
 
   void SetSampleTime(const TimeStamp& aSampleTime);
-  bool PushStateToWR(wr::TransactionWrapper& aTxn);
+  void SampleForWebRender(wr::TransactionWrapper& aTxn);
 
   bool SampleAnimations(const LayerMetricsWrapper& aLayer,
                         const TimeStamp& aSampleTime);

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -590,9 +590,9 @@ APZCTreeManager::UpdateHitTestingTree(LayersId aRootLayerTreeId,
                            aOriginatingLayersId, aPaintSequenceNumber);
 }
 
-bool
-APZCTreeManager::PushStateToWR(wr::TransactionWrapper& aTxn,
-                               const TimeStamp& aSampleTime)
+void
+APZCTreeManager::SampleForWebRender(wr::TransactionWrapper& aTxn,
+                                    const TimeStamp& aSampleTime)
 {
   AssertOnSamplerThread();
   MutexAutoLock lock(mMapLock);
@@ -648,7 +648,16 @@ APZCTreeManager::PushStateToWR(wr::TransactionWrapper& aTxn,
   }
   aTxn.AppendTransformProperties(scrollbarTransforms);
 
-  return activeAnimations;
+  if (activeAnimations) {
+    RefPtr<CompositorController> controller;
+    CompositorBridgeParent::CallWithIndirectShadowTree(mRootLayersId,
+      [&](LayerTreeState& aState) -> void {
+        controller = aState.GetCompositorController();
+      });
+    if (controller) {
+      controller->ScheduleRenderOnCompositorThread();
+    }
+  }
 }
 
 // Compute the clip region to be used for a layer with an APZC. This function

gfx/layers/apz/src/APZCTreeManager.h

@@ -215,17 +215,14 @@ public:
 
   /**
    * Called when webrender is enabled, from the sampler thread. This function
-   * walks through the tree of APZC instances and tells webrender about the
-   * async scroll position. It also advances APZ animations to the specified
-   * sample time. In effect it is the webrender equivalent of (part of) the
-   * code in AsyncCompositionManager. If scrollbar transforms need updating
-   * to reflect the async scroll position, the updated transforms are appended
-   * to the provided transaction as well.
-   * Returns true if any APZ animations are in progress and we need to keep
-   * compositing.
+   * populates the provided transaction with any async scroll offsets needed.
+   * It also advances APZ animations to the specified sample time, and requests
+   * another composite if there are still active animations.
+   * In effect it is the webrender equivalent of (part of) the code in
+   * AsyncCompositionManager.
    */
-  bool PushStateToWR(wr::TransactionWrapper& aTxn,
-                     const TimeStamp& aSampleTime);
+  void SampleForWebRender(wr::TransactionWrapper& aTxn,
+                          const TimeStamp& aSampleTime);
 
   /**
    * Walk the tree of APZCs and flushes the repaint requests for all the APZCS

gfx/layers/apz/src/APZSampler.cpp

@@ -62,6 +62,16 @@ APZSampler::SetSamplerThread(const wr::WrWindowId& aWindowId)
   }
 }
 
+/*static*/ void
+APZSampler::SampleForWebRender(const wr::WrWindowId& aWindowId,
+                               wr::Transaction* aTransaction)
+{
+  if (RefPtr<APZSampler> sampler = GetSampler(aWindowId)) {
+    wr::TransactionWrapper txn(aTransaction);
+    sampler->SampleForWebRender(txn);
+  }
+}
+
 void
 APZSampler::SetSampleTime(const TimeStamp& aSampleTime)
 {
@@ -70,11 +80,9 @@ APZSampler::SetSampleTime(const TimeStamp& aSampleTime)
   mSampleTime = aSampleTime;
 }
 
-bool
-APZSampler::PushStateToWR(wr::TransactionWrapper& aTxn)
+void
+APZSampler::SampleForWebRender(wr::TransactionWrapper& aTxn)
 {
-  // This function will be removed eventually since we'll have WR pull
-  // the transforms from APZ instead.
   AssertOnSamplerThread();
   TimeStamp sampleTime;
   { // scope lock
@@ -86,7 +94,7 @@ APZSampler::PushStateToWR(wr::TransactionWrapper& aTxn)
     // anyway, so using Timestamp::Now() should be fine.
     sampleTime = mSampleTime.IsNull() ? TimeStamp::Now() : mSampleTime;
   }
-  return mApz->PushStateToWR(aTxn, sampleTime);
+  mApz->SampleForWebRender(aTxn, sampleTime);
 }
 
 bool
@@ -247,12 +255,14 @@ APZSampler::GetSampler(const wr::WrWindowId& aWindowId)
 void
 apz_register_sampler(mozilla::wr::WrWindowId aWindowId)
 {
+  mozilla::layers::APZSampler::SetSamplerThread(aWindowId);
 }
 
 void
 apz_sample_transforms(mozilla::wr::WrWindowId aWindowId,
                       mozilla::wr::Transaction *aTransaction)
 {
+  mozilla::layers::APZSampler::SampleForWebRender(aWindowId, aTransaction);
 }
 
 void

gfx/layers/wr/WebRenderBridgeParent.cpp

@@ -532,12 +532,12 @@ WebRenderBridgeParent::UpdateAPZScrollData(const wr::Epoch& aEpoch,
   }
 }
 
-bool
-WebRenderBridgeParent::PushAPZStateToWR(wr::TransactionBuilder& aTxn)
+void
+WebRenderBridgeParent::SetAPZSampleTime()
 {
   CompositorBridgeParent* cbp = GetRootCompositorBridgeParent();
   if (!cbp) {
-    return false;
+    return;
   }
   if (RefPtr<APZSampler> apz = cbp->GetAPZSampler()) {
     TimeStamp animationTime = cbp->GetTestingTimeStamp().valueOr(
@@ -549,13 +549,7 @@ WebRenderBridgeParent::PushAPZStateToWR(wr::TransactionBuilder& aTxn)
       animationTime += frameInterval;
     }
     apz->SetSampleTime(animationTime);
-    // The TransactionWrapper shares the underlying transaction object with
-    // aTxn. When we exit this scope the TransactionWrapper is destroyed but
-    // the underlying transaction lives on in aTxn.
-    wr::TransactionWrapper txn(aTxn.Raw());
-    return apz->PushStateToWR(txn);
   }
-  return false;
 }
 
 mozilla::ipc::IPCResult
@@ -1248,15 +1242,10 @@ WebRenderBridgeParent::CompositeToTarget(gfx::DrawTarget* aTarget, const gfx::In
     ScheduleGenerateFrame();
   }
   // We do this even if the arrays are empty, because it will clear out any
-  // previous properties stored on the WR side, which is desirable. Also, we
-  // must do this before the PushAPZStateToWR call which will append more
-  // properties, If we did this after that call, this would clobber those
-  // properties.
+  // previous properties store on the WR side, which is desirable.
   txn.UpdateDynamicProperties(opacityArray, transformArray);
 
-  if (PushAPZStateToWR(txn)) {
-    ScheduleGenerateFrame();
-  }
+  SetAPZSampleTime();
 
   wr::RenderThread::Get()->IncPendingFrameCount(mApi->GetId());
 

gfx/layers/wr/WebRenderBridgeParent.h

@@ -220,11 +220,8 @@ private:
 
   CompositorBridgeParent* GetRootCompositorBridgeParent() const;
 
-  // Have APZ push the async scroll state to WR. Returns true if an APZ
-  // animation is in effect and we need to schedule another composition.
-  // If scrollbars need their transforms updated, the transaction builder
-  // is populated with the property update details via AppendTransformProperties
-  bool PushAPZStateToWR(wr::TransactionBuilder& aTxn);
+  // Tell APZ what the subsequent sampling's timestamp should be.
+  void SetAPZSampleTime();
 
   wr::Epoch GetNextWrEpoch();
 

gfx/webrender_bindings/src/bindings.rs

@@ -1173,7 +1173,6 @@ pub extern "C" fn wr_transaction_scroll_layer(
     scroll_id: u64,
     new_scroll_origin: LayoutPoint
 ) {
-    assert!(unsafe { is_in_compositor_thread() });
     let scroll_id = ExternalScrollId(scroll_id, pipeline_id);
     txn.scroll_node_with_id(new_scroll_origin, scroll_id, ScrollClamping::NoClamping);
 }

modules/libpref/init/all.js

@@ -854,6 +854,7 @@ pref("gfx.compositor.glcontext.opaque", false);
 #endif
 
 pref("gfx.webrender.highlight-painted-layers", false);
+pref("gfx.webrender.async-scene-build", false);
 pref("gfx.webrender.blob-images", 1);
 pref("gfx.webrender.blob.invalidation", true);
 pref("gfx.webrender.hit-test", true);